Add X-Request-Start header so we can track queue times in New Relic RPM beginning at Varnish. - Modified by me for varnish 2.X

default.vcl

#
# Add X-Request-Start header so we can track queue times in New Relic RPM beginning at Varnish.
# Taken from https://gist.github.com/494265 & modified to compile on OSX.
#  

sub vcl_recv {
  // NewRelic X-Request-Start tracking
  C{
    #include </etc/varnish/newrelic.h>
  }C
  # ...
}

newrelic.h

/*
 * Add X-Request-Start header so we can track queue times in New Relic RPM beginning at Varnish.
 * Taken from https://gist.github.com/494265 & modified to compile on OSX.
 * Also check out http://www.paoloiannelli.com/2012/09/26/working-varnish-configuration-for-new-relic/
 */

#include <sys/time.h>
#include <stddef.h>
#include <stdio.h>

struct timeval detail_time;
gettimeofday(&detail_time, 0);
char start[20];
sprintf(start, "t=%lu%06lu", detail_time.tv_sec, detail_time.tv_usec);
VRT_SetHdr(sp, HDR_REQ, "\020X-Request-Start:", start, vrt_magic_string_end);